How to get AO in path tracing ?

How can I simulation AO in path tracing ?
It seems to be working with lumen but no dark shadows are appearing in objects colliding each others, how can I make a material on my landscape mesh that captures all objects interractions as in Blender ?

No one knows ?

Please

Up

21 views and not a single person knows how to get shadows around objects hitting surfaces as in Blender ??